<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>鼠标经过事件onmouseover</title>
    <script type="text/JavaScript">
        function feedback() {
            alert("卸载之前再想想吧...");
        }
    </script>
</head>
<body>
    <form action="get/post">
        <input type="button" value="卸载" 
            onmouseover="feedback();">
    </form>
</body>
</html>